editing Macaulay 2 code with emacs

In this section we learn how to use emacs to edit Macaulay 2 code. Assuming you have set up your emacs init file as described in running Macaulay 2 in emacs when you visit a file whose name ends with .m2 you will see on the mode line the name Macaulay 2 in parentheses, indicating that the file is being edited in Macaulay 2 mode. (Make sure that the file emacs/M2-mode.el is on your load-path.)

To see how electric parentheses, electric semicolons, and indentation work, move to a blank line of this file and type the following text.

f = () -> ( a := 4; b := {6,7}; a+b)

Observe carefully how matching left parentheses are indicated briefly when a right parenthesis is typed.

Now position your cursor in between the 6 and 7. Notice how pressing M-C-u moves you up out of the list to its left. Do it again. Experiment with M-C-f and M-C-b to move forward and back over complete parenthesized expressions. (In the emacs manual a complete parenthesized expression is referred to as an sexp, which is an abbreviation for S-expression.) Try out C-U 2 M-C-@ as a way of marking the next two complete parenthesized expression, and see how to use C-W to kill them and C-Y to yank them back. Experiment with M-C-K to kill the next complete parenthesized expression.

Position your cursor on the 4 and observe how M-; will start a comment for you with two hyphens, and position the cursor at the point where commentary may be entered.

Type res somewhere and then press C-C TAB to bring up the possible completions of the word to documented Macaulay 2 symbols.

Finally, notice how C-H m will display the keystrokes peculiar to the mode in a help window.